Integrated lamp with feedback and wireless control

ABSTRACT

A lamp assembly ( 50 ) employs a reflector ( 52 ) defining a light reflecting area ( 53 ), and a heat sink ( 54 ) defining a circuit housing area ( 55 ). A LED assembly ( 51 ) is disposed within the light reflecting area ( 53 ) and heat sink ( 54 ) dissipates heat away from LED assembly ( 51 ). One or more LEDs of LED assembly ( 51 ) emit a light in response to a flow of a LED current through the LEDs. One or more optical power sensors of LED assembly ( 51 ) sense an emission of the light by LED(s). A LED driver circuit ( 30 ) is disposed within the circuit housing area ( 55 ) to control the flow of the LED current through the LED(s) as a function of a sensing of the emission of the light by the optical power sensor(s) and a desired level of one or more lighting variables associated with the LED(s).

The present invention relates to light emitting diodes (LEDs) andoptical power sensors integrated in a lamp housing. More specifically,the present invention relates to LEDs and optical power sensorsintegrated in a lamp housing with the lamp driver circuits to providefeedback and remote control of the lamp.

Most artificial light is produced by an electric discharge through a gasin a lamp. One such lamp is the fluorescent lamp. Another method ofcreating artificial light includes the use of a LED, which provides aspectral output in the form of a radiant flux that is proportional to aforward current flowing through the LED. Additionally, a LED lightsource can be used for generation of a multi-spectral light output.

Conventional LED light sources utilize individual encapsulated lightemitting diodes or groups of light emitting diodes of substantiallysimilar spectral characteristics encapsulated as a unit. ConventionalLED light sources are implemented as color corrected LED light sources.Color corrected LED light sources are manufactured by applying aphosphor compound layer to a LED, either directly or within anencapsulent. The phosphor layer absorbs the light emitted by the LED ora portion of the light emitted by the LED and emits light based on aninteraction of the absorbed light and the phosphor compound. The colorcorrected LED light sources are grouped together to form the LED lightsource. Color corrected LEDs realize maximum accuracy in spectral outputwhen a specified amount of direct current is applied to the colorcorrected LEDs. The specified amount of direct current, among otherdata, is included in a rating for each color corrected LED.

Combining the output of multiple colored LEDs in a lamp is an alternateway to form a white light source. Such combinations offer the option ofproducing a variety of colors. It is a difficult problem to combine andmaintain correct proportions of light from multi-colored LEDs to createlight that is of desired color and intensity as well as reasonablespatial uniformity, because LED spectra and efficiencies change withcurrent, temperature and time. In addition, LED properties vary from LEDto LED, even from a single manufacturing batch. As LED manufacturingimproves with time, LED-to-LED variations may become smaller, but LEDvariations with temperature, current, and time are fundamental to thesemiconductor devices. Conventional control systems, in someembodiments, adjust intensity levels of spectral output by increasing ordecreasing the number of LEDs receiving the specified amount of directcurrent.

It is desirable to have an integrated lamp with a feedback mechanism toensure the desired lamp illumination characteristics whereinillumination sensors, LEDs and control circuitry are integrated within alamp housing which is operable to reflect a portion of emitted lightback to the photosensors for system feedback. It is also desirable thatthe controlled illumination characteristics include emitted intensityand color, which may vary as a function of time as indicated by inputreceived from a remote radio frequency source.

One form of the present invention is a lamp assembly comprising areflector, a heat sink, a LED assembly and a LED driver circuit. Thereflector defines a light reflecting area. The heat sink defines acircuit housing area. The LED assembly is disposed within the lightreflecting area and in thermal communication with the heat sink todissipate heat away from the LED assembly. The LED assembly includes oneor more LEDs operable to emit a light in response to a flow of a LEDcurrent through the LED assembly. The LED assembly also includes one ormore optical power sensors operable to sense an emission of the light bythe LED(s). The LED driver circuit is disposed within the circuithousing area, and is in electrical communication with the LED assemblyto control the flow of the LED current through the LED(s) as a functionof a sensing of the emission of the light by the optical powersensor(s).

The term “thermal communication” is defined herein as a physicalconnection, a physical coupling, or any other technique for thermallytransferring heat from one device to another device.

The term “electrical communication” is defined herein as an electricalconnection, an electrical coupling or any other technique forelectrically applying an output of one device to an input of anotherdevice.

The foregoing form as well as other forms, features and advantages ofthe present invention will become further apparent from the followingdetailed description of the presently preferred embodiments, read inconjunction with the accompanying drawings. The detailed description anddrawings are merely illustrative of the present invention rather thanlimiting, the scope of the present invention being defined by theappended claims and equivalents thereof.

FIG. 1 illustrates one embodiment of a LED system in accordance with thepresent invention;

FIG. 2 illustrates one embodiment of a LED assembly in accordance withthe present invention; and

FIG. 3 illustrates a cross-sectional view of one embodiment of a lampassembly in accordance with one embodiment of the present invention.

A light emitting diode system 10 illustrated in FIG. 1 employs a LEDassembly 20, a LED driver assembly 30, and a remote controller 40. LEDassembly 20 includes one or more light emitting diodes (“LEDs”) 21 witheach LED being arranged individually or in an array, and one or moreoptical power sensors (“OPSNR”) 22. LED driver assembly 30 includes acontroller (“CONT”) 31, a power circuit (“PWRC”) 32, an antenna 34, atransceiver (“TX/RX”) 35, a signal processor (“SP”) 36, and an errordetector 37.

Optical power sensors 22 sense any emission of light from LEDs 21. Inone embodiment, optical power sensors 22 are a plurality of photosensorswhere each photosensor is responsive to a different specific range ofwavelengths. In a second embodiment, optical power sensors 22 arearranged in groups of photosensors where each photosensor group isresponsive to a different specific range of wavelengths. In a thirdembodiment, optical power sensors 22 are a plurality of photosensorswhere each photosensor is responsive to the same range of wavelengths.

Optical power sensors 22 electrically communicate one or more sensingsignals SEN indicative of a sensing an emission of light from LEDs 21.In one embodiment, optical power sensors output current signalsindicative of the sensing of the emission of light from LEDs 21, and anoperational amplifier (not shown) converts the current signals intovoltage signals, and electrically communicates the voltage signals tosignal processor 36.

In practice, the structural construction of LED assembly 20 is dependentupon commercial implementations of LED assembly 20. FIG. 2 illustratesone structural construction of light emitting diode (LED) assembly 20(FIG. 1) employing LEDs 21 and optical power sensors 22 formed on orattached to a substrate 23. In this embodiment, the LEDs 21 consist ofrows of LED arrays, specifically, a row of red LED arrays LA_(R), a rowof green LED arrays LA_(G), a row of blue LED arrays LAB and a row ofamber LED arrays LA_(A). Optical power sensors 22 consist of photosensors (“PS”) placed between neighboring LED arrays.

Referring again to FIG. 1, signal processor 36 determines a sensed lightvalue SLV indicative of the sensing of the emission of light from LEDs21, and electrically communicates the sensed light value SLV to errordetector 37. In one embodiment, error detector 37 is an adder, as shown,and signal processor 36 electrically communicates sensed light value SLVto a negative input of the adder. In a second embodiment, error detector37 is an operation amplifier with a dual input, and signal processor 36electrically communicates sensed light value SLV to an inverting inputof the operational amplifier.

A user of LED system 10 can operate remote controller 40 to transmit acontrol signal CS1 to antenna 34 where control signal CS1 is indicativeof a desired emission of light from LEDs 21. Antenna 34 electricallycommunicates control signal CS1 to transceiver 35, which selectivelyconverts control signal CS1 into a desired lighting value DLV indicativeof the desired emission of light from LEDs 21, and electricallycommunicates the desired lighting value DLV to error detector 37. In oneembodiment, error detector 37 is an adder as shown and transceiver 35electrically communicates desired light value DLV to a positive input ofthe adder. In a second embodiment, error detector 37 is an operationamplifier with a dual input, and transceiver 35 electricallycommunicates desired light value DLV to a non-inverting input of theoperational amplifier.

Error detector 37 compares the desired light value DLV and the sensedlight value SLV, and electrically communicates a correction light valueCLV to controller 31 where the correction light value CLV is indicativeof a differential between the desired light value DLV and the sensedlight value SLV. Controller 31 employs conventional circuitry fordetermining whether a change in the output power levels of LEDs 21 isrequired in view of the correction light value CLV, and to communicate aLED control signal CS2 to power circuit 32 where LED control signal CS2is indicative of any change that needs to take place in the output powerlevels of LEDs 21. Power circuit 32 employs a power integrated circuit(“PWR IC”) 33 to conventionally receive an electrical power PWR requiredto drive the circuits described herein, and to supply a direct currentI_(LED) to LEDs 21 based on the required optical power levels of LEDs 21as indicated by LED control signal CS2.

Additionally, in one embodiment of the present invention, a user of LEDsystem 10 can operate remote controller 40 to transmit a control signalCS3 to antenna 34 where control signal CS3 is indicative of a softwareprogram to be stored in a controller 31, wherein controller 31 is aprogrammable controller. Antenna 34 electrically communicates controlsignal CS3 to transceiver 35, which selectively converts control signalCS3 into a control signal CS4 indicative of the desired software programto be stored in the controller, and electrically communicates thedesired software program to controller 31 to be stored. When the storedprogram is to be implemented, controller 31 electrically communicates acontrol signal CS5 to transceiver 35 where control signal CS5 isindicative of a desired emission of light from LEDs 21 in view of thesoftware program stored in memory. Transceiver 35 selectively convertscontrol signal CS5 into the desired light value DLV. In one embodiment,control signal CS1 overrides control signal CS5 whereby transceiver 35converts control signal CS1 into desired lighting value DLV whenevertransceiver 35 receives a concurrent communication of controls signalsCS1 and CS5 from antenna 34 and controller 31, respectively. In a secondembodiment, control signal CS5 overrides control signal CS1 wherebytransceiver 35 converts control signal CS5 into desired lighting valueDLV whenever transceiver 35 receives a concurrent communication ofcontrols signals CS1 and CS5 from antenna 34 and controller 31,respectively.

In practice, a structural configuration of each component of LED driverassembly 30 is dependent upon the commercial implementations of LEDdriver assembly. In one embodiment, LED driver assembly 30 isconstructed in accordance with (1) U.S. Patent Application PublicationUS2001/0024112 A1 published Sep. 27, 2001, and entitled “Supply AssemblyFor A LED Lighting Module”, (2) United States Patent ApplicationPublication US2003/0085749 A1 published May 8, 2003, and entitled“Supply Assembly For A LED Lighting Module”, (3) U.S. patent applicationSer. No. 60/468,538 filed on May 7, 2003, and entitled “Single DriverFor Multiple Light Emitting Diodes”, (4) U.S. patent application Ser.No. 10/323,445 filed Dec. 19, 2002, and entitled “Supply Assembly For AnLED Lighting Module”, and/or (5) U.S. patent application Ser. No.60/468,553 filed May 7, 2003, and entitled “Current Control Method andCircuit for Light Emitting Diodes”, all of which are hereby incorporatedby reference and assigned to the assignee of this application.

FIG. 3 illustrates a lamp assembly 50 and a remote control 41implementing LED system 10 (FIG. 1). Lamp assembly 50 employs a LEDassembly 51 (an implementation of LED assembly 20 shown in FIG. 1), areflector 52 having an inner surface defining a light reflecting area53, a heat sink 54 having an inner surface defining a circuit housingarea 55, thermal conductors 56 and 57, a mounting board 58, a powercircuit 59 (an implementation of power circuit 32 shown in FIG. 1), acircuit board 60, and an antenna 66 (an implementation of antenna 34shown in FIG. 1). LED assembly 51 is disposed within light reflectingarea 53 and in thermal communication with heat sink 54 to dissipate heataway from LED assembly 51.

Mounting board 58, power circuit 59 and circuit board 60 are disposedwithin circuit housing area 55. Mounting board 58 is attached to heatsink 54 via thermal conductors 56 and 57, which provide thermallyconductive paths to draw the heat from the LED assembly 51 to the heatsink 54. Mounting board 58 supports power circuit 59 and circuit board60 as shown. Electrically mounted on circuit board 60 are a controller61 (an implementation of controller 30, signal processor 36, and errordetector 37 shown in FIG. 1), a transceiver 62 (an implementation oftransceiver 35 shown in FIG. 1), and electronic components in the formof a capacitor 63, a resistor 64 and an inductor 65.

Remote control 41 incorporates remote controller 40 (FIG. 1), which mayinclude, but is not limited to, a handheld computer, a lap top, adedicated computer, or a personal digital assistant (PDA), to transmit aradio frequency signal responsive to input from a user (not shown). Thetransmitted radio frequency signal will be received by an antenna 66.The user may input a variety of lighting variables associated with theemission of the light by LED assembly 51 including, but not limited to,light intensity levels, light color levels, color temperature levels andtime. The user may input programs to modify one or more of these variousparameters as a function of time.

In one embodiment, the user programs the remote control 41, using akeypad, with a lighting program to control a variety of lightingvariables associated with the emission of the light by LED assembly 51over a period of time. The program may be transmitted as delayed signalsbased on the program to the lamp assembly 50 in order to vary the lightparameters over time. The program may start immediately upon beinginput, the program may start at a preprogrammed future time or theprogram may start periodically at a preprogrammed future times.

In a second embodiment, the user uses a keypad on the remote control 41to program the remote control 41 with multiple sets of software code.Each set of software code will control at least one of a variety oflighting variables associated with the emission of the light by at leastone LED array, wherein the changes in lighting variables will beimplemented at specific preprogrammed times. One of the multiple sets ofsoftware code may be initiated by a keystroke sequence on a keypad ortouchscreen (not labeled) on the remote controller for immediate, futureor periodic activation.

In a third embodiment, the user downloads one set of software code fromthe remote control 41 to controller 31, as control signal CS3 totransceiver 35, which selectively converts control signal CS3 into acontrol signal CS4 as described above. The downloaded set of softwarecode may be implemented to control the emission of light from lampassembly 50 immediately upon download, it may be implemented at a futuretime as programmed or it may be implemented periodically as programmed.

In a fourth embodiment, the user downloads multiple sets of softwarecode from the remote control 41 to controller 31. Any one of thedownloaded sets of software code may be implemented to control theemission of light from lamp assembly 50 immediately upon download, orany one of the downloaded sets of software code may be implemented at afuture time as programmed or any one of the downloaded sets of softwarecode may be implemented periodically as programmed. Alternately, any oneof the downloaded sets of software code may be initiated by a keystrokesequence on a keypad or touchscreen (not labeled) on the remotecontroller for immediate, future or periodic activation. Such akeystroke sequence on a keypad or touchscreen will transmit a radiofrequency signal to be received at the antenna 66 at the lamp assembly50.

As previously mentioned, antenna 66 receives a radio frequency signalfrom remote control 41 and electrically communicates the signal totransceiver 62 via a cable (not shown). In one embodiment, the cable isextended through light reflecting area 53 from antenna 66 to circuitboard 60. In a second embodiment, the cable extends along an outersurface of reflector 54 and enters circuit housing area 55 through theheat sink 54.

Within light reflecting area 53, reflector 52 contains a lightreflecting material LRM, which is, at least partially, opticallytransparent to the light emitted from the LED assembly 51. The lightreflecting material LRM contained in reflector 52 is, in one embodiment,a silicone, such as, for example, a Nye two-part silicone (part numbersOC-97228A-1 and OC-97228B-1). The interface between air and the surfaceof the light reflecting material LRM (not shown) reflects a portion ofthe light emitted from the LED assembly 51 back towards the LED assembly51. The optical power sensors 22 (FIG. 2) of LED assembly 51 detect theoptical power reflected at the air interface with light reflecting area53. The optical power sensors 22 are in electrical communication withthe controller 61 via trace lines and/or via in or on mounting board 58and circuit board 60.

Optical scattering particles may, in one embodiment, be mixed into thelight reflecting material LMR to mix the light emitted by the LEDs onLED assembly 51 and to reflect the light back to the optical powersensors on the LED assembly 51.

The interface between the air and the surface of the light reflectingmaterial LRM may be shaped to direct more or less reflected opticalpower to the LED assembly 51. Alternately, the interface between the airand the surface of the light reflecting material LRM may be shaped toappropriately mix the emission of various colored LEDs reflected back toLED assembly 51. Such mixing will allow the reflected power to replicatethe mix of the emission of various colored LEDs at a point outside thelamp assembly 50. Alternately, an additional element, such as, forexample, a lens, a filter, or a diffuser may be attached to the frontsurface of the lamp assembly 50 to affect the shape, direction or colorof the light emitted from the lamp assembly 50.

The electrical power required to drive the circuits is delivered byplacing a lamp base 67 into a conventional light socket. The electricalconnections from the lamp base 67 to power circuit 58 and circuit board60 are not illustrated but, one skilled in the art, can envisionnumerous ways to apply electrical power to power circuit 59 and circuitboard 60.

The lamp assembly 50 and a remote control 41 implementing LED system 10(FIG. 1) provide numerous functions. The variables controlled includetiming information to control the color and intensity, as well asdimming level. Information about the status of the lamp operation, suchas, for example, the status of the operation of LED 21 or the LEDassembly 51 may be obtained. Such status information may be used todetermine if either is no longer operational and needs repair based onperiodic lamp assembly 50 status checks programmed into the remotecontroller 40 or the controller 31. Information about the ambient lightlevels may be utilized to cause the lamp to adjust the output level soas to not waste energy or to adapt its color to maintain a preferredambiance.

Additionally, for safety and security purposes, the lamp may have analarm mode to be used when an unauthorized person enters the room and isdetected by a sensor, which can communicate the intrusion to the lampdirectly or via another link. The lamp may then be turned on to allowfor a clear video image to be obtained with an installed camera. A lightbeing turned on in the room may also panic the intruder causing theintruder to flee. A pre-programmed “fire” mode may also be used to helpfiremen see more clearly during a rescue. White light in smoke usuallyhinders visibility, so the system may be programmed to emit red light toenhance visibility to those in the room.

The illustrated embodiment of lamp assembly 50 is meant to illustrate astructure to provide light reflection within the lamp assembly 50 tooptical power sensor(s) to be used as feedback in the operation of aremotely controlled or programmed circuit to control LED(s) to obtain adesired light level and is not intended to be exhaustive of allpossibilities or to limit what can be fabricated for the aforementionedpurpose. There is therefore a multiplicity of other possiblecombinations and embodiments. By using what is shown and describedherein, a remote control 41 communicates with the lamp assembly 50 toobtain at least one desired light level parameter. Those having ordinaryskill in the art will therefore appreciate the benefit of employing anembodiment of lamp assembly 50 in numerous and various devices.

In the foregoing specification, the invention has been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the present invention as set forthin the claims below. Accordingly, the specification and figures are tobe regarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope ofpresent invention.

1. A lamp assembly (50), comprising: a reflector (52) defining a lightreflecting area (53); a heat sink (54) defining a circuit housing area(55); a LED assembly (20) disposed within said light reflecting area(53) and in thermal communication with said heat sink (54) to dissipateheat away from said LED assembly (20), said LED assembly (20) includingat least one LED (21) operable to emit a light in response to a flow ofa LED current (I_(LED)) through said at least one LED (21), and at leastone optical power sensor (22) operable to sense an emission of the lightby said at least one LED (21); and a LED driver circuit (30) disposedwithin said circuit housing area (55), said LED driver circuit inelectrical communication with said LED assembly (20) to control the flowof the LED current (I_(LED)) through said at least one LED (21) as afunction of a sensing of the emission of the light by said at least oneoptical power sensor (22).
 2. The lamp assembly (50) of claim 1, whereinsaid LED driver circuit (30) includes: a transceiver (35) operable toreceive a communication of at least one lighting variable associatedwith the emission of the light by said at least one LED (21), whereinthe flow of the LED current (I_(LED)) through said at least one LED (21)is a function of the sensing of the emission of the light by said atleast one photo sensor (22) and a reception of the communication of theat least one lighting variable by said transceiver (37).
 3. The lampassembly (50) of claim 2, further comprising: an antenna (36) operableto transmit the communication of the at least one lighting variable tosaid transceiver (35).
 4. The lamp assembly (50) of claim 2, furthercomprising: a controller (31) in electric communication with saidtransceiver (35) to communicate a LED control signal (CS5) indicative ofthe at least one lighting variable to said transceiver (35).
 5. The lampassembly (50) of claim 2, wherein said LED driver circuit (40) furtherincludes: an error detector (37) for generating a correction light value(CLV) indicative of a differential between a sensed light value (SLV)and a desired light value (DLV), the sensed light value (SLV) beingindicative of the sensing of the emission of the light by said at leastone optical power sensor (22), the desired light value (DLV) beingindicative of the reception of the communication of the at least onelighting variable by said transceiver (35).
 6. The lamp assembly (50) ofclaim 5, wherein said LED driver circuit (30) further includes: acontroller (31) in electrical communication with said error detector(37) to receive the correction light value (CLV), said controller (31)operable to generate a LED control signal (CS2) as a function of thecorrection light value (CLV).
 7. The lamp assembly (50) of claim 6,wherein said LED driver circuit (30) further includes: a power circuit(32) in electrical communication with said controller (31) to receivethe LED control signal (CS2), said power circuit (32) operable to directthe flow of the LED current (I_(LED)) through said at least one LED (21)as a function of the LED control signal (CS2).
 8. The lamp assembly (50)of claim 1, wherein said at least one LED (21) includes a plurality ofLED arrays (LED_(R), LED_(G), LED_(B), LED_(T)).
 9. A lamp assembly(50), comprising: a reflector (52) defining a light reflecting area(53); a heat sink (54) defining a circuit housing area (55); a LEDassembly (20) disposed within said light reflecting area (53) and inthermal communication with said heat sink (54) to dissipate heat awayfrom said LED assembly (20), said LED assembly (20) including LED means(LED_(R), LED_(G), LED_(B), LED_(A)) for emitting a light in response toa flow of a LED current (I_(LED)) through said LED means (LED_(R),LED_(G), LED_(B), LED_(A)), and optical sensor means (PS) for sensing anemission of the light by said LED means (LED_(R), LED_(G), LED_(B),LED_(A)); and a LED driver circuit (30) disposed within said circuithousing area (55), said LED driver circuit including means (31-37) forcontrolling the flow of the LED current (I_(LED)) through said LED means(LED_(R), LED_(G), LED_(B), LED_(A)) as a function of a sensing of theemission of the light by said optical sensor means (PS).